The present invention relates to an electronic musical instrument and, more particularly, to an electronic musical instrument in which a plurality of types of rhythm sound sources can be operated by a minimum number of operating members.
In some conventional electronic musical instruments of this type, when one of the keys on a keyboard is depressed, one of a plurality of rhythm sound sources is assigned to the depressed key (U.S. Pat. No. 4,672,876).
In this conventional arrangement, an arbitrary rhythm sound source can be assigned to each of the keys on a keyboard originally used for generating main musical tones consisting of a melody and a chord. Therefore, as compared with an arrangement in which a specific selecting operating member is individually assigned to each rhythm sound source, the overall arrangement can be simplified.
If keys are assigned as performance operating members to rhythm sound sources in a one-to-one relation, however, a large number of keys are required for designating the type of rhythm sound source, resulting in a still complex overall arrangement. In addition, a performer must execute a cumbersome operation for selecting one or a plurality of arbitrarily assigned rhythm sound sources upon a performance. This operation cannot be easily done during a performance even if the performer wants to change the rhythm sound source.
In some conventional automatic rhythm apparatus of this type, a rhythm/tone color designating button (commonly referred to as a "white button") to which no specific function is assigned is used as an operating means for changing a rhythm performance state (Japanese Patent Laid-Open (Kokai) Nos. 62-187893 and 61-176991).
This automatic rhythm apparatus, however, must switch a variety of performance states such as start and stop of a rhythm performance, switching between rhythm sound sources, switching between rhythm patterns, and insertion of fill-in. Therefore, a large number of operating members are required if they are assigned to the respective performance states in a one-to-one relation. As a result, switching labors of a performer are increased.
In the conventional automatic rhythm apparatus of this type, in order to adjust a volume of a rhythm performance tone, a rhythm volume knob is arranged on an operation panel in addition to other operating members and used to adjust the volume during a rhythm performance.
In this case, if a volume, a pattern or the like can be changed as needed during a rhythm performance so as not to allow a rhythm performance tone to be monotonous, e.g., if the rhythm tone can be controlled to be a hot or cool impression as needed during a performance, the above automatic rhythm apparatus can be functionally advanced.
In the above conventional arrangement, however, a performer usually operates performance operating members such as keys or pads during a rhythm performance. Therefore, it is practically impossible to adjust the volume or the like of a rhythm tone during a performance.
As disclosed in Japanese Patent Laid-Open (Kokai) No. 61-282896, a conventional apparatus of this type comprises an assigning means for assigning an arbitrary one of a larger number of types of tones than a plurality of operating members to each operating member, and a tone generation control means for supplying data representing a tone assigned to an operated operating member to a tone signal generating means in response to an operation of each of the plurality of operating members, thereby controlling generation of the tone executed by the tone signal generating means. In this manner, after the assigning means assigns an arbitrary tone to each operating member, the assigned tone is generated upon operation of the operating member, thereby generating a larger number of tones by a smaller number of operating members.
In the above conventional apparatus, however, it is difficult to change assignment of a tone to an operating member during a performance. Therefore, only tone signals in number equal to that of operating members can be generated in one piece of music.